/*
 * Copyright 2020-2030 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * 斐波那契数列解
 *
 * @author Created by Neil Wang
 * @version 1.0.0
 * @date 2021/6/24 3:23 下午
 */
public class Solution {

    public Integer solute(int i) {
        if (i <= 0) throw new IndexOutOfBoundsException("You cannot input a negative number.");
        return solute(0, 1, i);
    }

    private Integer solute(int var1, int var2, int index) {
        if (index == 1) return var2;
        return solute(var2, var1 + var2, --index);
    }
}
